New Deposits of Rare Earths Ores in Tanzania Substitute for China?

Rare earth metals are the new black in mining circles — everywhere you turn, whether it is a mining conference or a trade journal, the focus is on finding and developing new sources of supply to counter the perceived threat posed by Chinese dominance of the supply market. In reality, rare earths (RE) are anything but rare in the words of Dr. Roger Paul, general manager of business development at South Africa’s center of excellence in mineral and metallurgical technologies, Mintek. The elements are widely distributed in the earth’s crust, but often not in sufficient concentration to support commercial extraction. One resource that may be the case (and the reason for our conversation with Dr. Paul) is Montero’s Wigu Hill deposit in Tanzania, covered by Mineweb in an article this week.

Apparently Wigu Hill has a lot going for it, both geologically and geographically. Geologically, because the deposit is carbonatite in form with no associated radioactive materials present such as uranium or thorium, and while it potentially adds a revenue stream, it also greatly complicates the handling, concentrating and refining processes. Concentration is another facet of the geological advantages in Wigu’s favor. In places, concentration goes as high as 25 percent, but is likely to average 7 to 10 percent, according to the article. The other advantage is Tanzania’s geographic proximity to world-class mining, processing and refining expertise in neighboring South Africa. Dr. Paul explained that twenty years ago South Africa developed an effective extraction process to refine RE salts from Gypsum tailings, but the commercial exploitation was dropped for want of scale. The project required a minimum of 2,000 tons of feedstock per year and the resource was of too low a grade to achieve that. New interest has now developed on higher grade deposits and technically, facilities could be developed in conjunction with Wigu Hill.

In reality, though, Dr. Paul believes refining capability will either be developed in North America or Europe or both to meet growing demand for rare earth metals from the host of emerging green technologies. Intriguingly, Dr. Paul mentioned the capabilities of French chemicals company Rhône-Poulenc in the refining of these elements. Apparently back in the 1990s prior to the dominance of China’s Bayan Obo mine and development of China’s numerous associated refining ventures, Rhone-Poulenc was refining rare earth metals. The firm subsequently spun the refining operation off into a separate company called Rhodia Rare Earths which today has facilities in France, the US and Japan. We tried contacting the company to ask if their facilities were still in full operation and to better understand their ability to meet western demand in the event that new ore bodies were exploited. Unfortunately, nobody from the company was able or willing to be interviewed, so their capability remains uncertain. Certainly expansion or refurbishment of such facilities should be more economical than developing new refining capabilities. More important, the firm should still have the technical expertise that appears in such short supply outside of China.

–Stuart Burns

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